Caracterização de famílias de alface quanto à resistência aos nematóides das galhas (Meloidogyne spp.),tolerância ao pendoamento precoce e características comerciais

Abstract

Lettuce yeids under higt temperature have been negatively affected by tendency to carly bolting and by root knot nematodes (Meloidogyne spp.) Resistante cultivars would be a sound alternative for cultivation inder these conditions.The present paper reports on the screening of new lettuce breending lines for tolerance to early bolting, resistance to root knot nematodes and commercially desirable traits,in an attempt to identify suitable loose-leaf lines with crinkled lines. Five different experiments were carried ot in two different esperimantal phases, starting from the f2 generation of crosses between the cultivar Verônica and previously selects breeding lines derived from the cross (Grand Rapids x regina 71). In the fist phase two experiments in randomized complete blocks (RCB) designs were established in order to selected plants were reistent to both nematodes and early bolting Seed were harvested from 60 different selected families. A 39 families sample was accessed in the second phase, in a set of thee esperiments. Two esperiments were designed to evaluate commercial traits (leaf lib and bordes type and leaf mass) and nematode resistance. Nine families, FX-009A-17,AFX-009A-51,AFX0009A-78,AFX-011-07,AFX-011A-12,AFX-011A-52,AFX-012A- 46,AFX-012ª-49E AFX-013-A-68, were homozygous for nematodes resistance. Among these, AFX-009-A-17,AFX-009ª-51,AFX011A-07,AFX-011ª-12 e AFX-013-A68 stood out for both early bolting and commercial traits.These lines may lead to cultivars that will be high yiending in áreas with high temperatures and high soil nematodes populations.